[clang-tools-extra] [libcxx] Unifying __is_trivial_equality_predicate and __is_trivial_plus_operation into __desugars_to (PR #68642)

[Louis Dionne via cfe-commits]

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@@ -18,8 +18,11 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Pred, class _Lhs, class _Rhs>
-struct __is_trivial_plus_operation : false_type {};
+template <class _Operation, class _Canonical>
+struct __desugars_to : false_type {};
+
+template <class _Operation>
+struct __desugars_to<_Operation, _Operation> : true_type {};
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ldionne wrote:

Now this one wouldn't actually make sense anymore, since `__desugars_to` would take an operation and a tag, not two operations.

https://github.com/llvm/llvm-project/pull/68642